Referencing Gregg's idea, another potential benefit of the color coding would be that a driver who's having a difficult time bleeding off speed (brake failure / malfunction) would be able to tell they were running out of real estate and have the decision available to use the wall to slow themselves down prior to entering the trap... I would think a side impact of the cement retaining wall, especially a controlled side impact of sorts, would be a lot nicer than going full-tilt boogie into the sand. Sure, it means damage to the car, but hitting the sand at that speed isn't exactly going to save the car - just ask Del. That option is obviously available to them today, even without the color coding, but I would think seeing green, turn to yellow then to red out the side windows would be a visual reminder of sorts, under already extreme conditions, that a decision needs to happen.
Obviously, I've never driven one myself so I could be way off track, but from my outsider's point of view, my thought is that it certainly couldn't hurt.
